Generally, locking pins are used for coupling rotor blades to rotors, such as turbine rotors. A typical turbine rotor assembly includes a rotor blade disk having a series of slots (e.g. finger joints) in its outer periphery and a rotor blade having corresponding slots configured to couple with the rotor blade disk. The root of the rotor blade, including the finger joints, may be locked into engagement with the rotor blade disk by one or more locking pins. A single rotor blade disk may have as many as several hundred locking pins.
While repairing or replacing rotor blades, the locking pins securing the blades to the rotor blade disks must be removed. This is typically accomplished by drilling through a centerline or axis of the locking pin. Because the length of various rotor blades is typically great, and the space between successive rotor blades is typically narrow, currently available drilling tools used for such processes are similarly long and relatively thin. This tool configuration leads to bending of the support arm during drilling operations. As a result of the bending, the drill may be misaligned with the axis of the locking pin. This may result in damage to the rotor blade and/or rotor blade disk as the drill “walks” off line during a drilling operation.
Also, the current tool configuration requires a machine that is relatively large in order to position and provide support for the support arm. Because of this size, the machine is cumbersome to setup and position during a repair. Furthermore, and as a partial product of the size and configuration of the tool, current practices do not permit alignment of the tool with a locking pin axis that is not parallel to the turbine rotor axis. If, for example, previous repairs have resulted in an off axis pin, it may not be possible to align current machines with a center line or axis of the locking pin.